The North American Slime-Moulds Part 61

Sporangia densely aggregated, forming cl.u.s.ters of greater or less extent, sometimes reaching several centimetres in either direction, tawny gray or ashen, cylindric, tapering a little above, when expanded reaching a length of half a centimetre or more, stipitate; peridium evanescent except the small shallow cup-like base, the calyculus; stipe long (1 mm.), weak, pale brown or reddish, tubular, the channel filled with plasmodic ma.s.ses; capillitium gray or drab-colored, very slightly attached to the bottom of the calyculus, far expanded, forming a loose-meshed net, the threads regular, cylindric, coa.r.s.ely sculptured with rings, half-rings, cogs, spines, etc.; spores in ma.s.s dull gray, drab, under the lens colorless, papillate, with few papillae, 7-8 .

This magnificent form resembles in habit and general appearance, save color, _A. nutans_. The capillitium is, however, very different both in the sculpture and in the more delicate markings of the threads. Dr. Rex, _l. c._, has pointed out the lack of reticulation on the capillitium and calyculus. The color is also diagnostic. A roseate variety seems to occur with the present form. This is _A. magna rosea_ Rex, and appears to agree with the type in all respects save color. The relationship here must be determined by future inquiry. The capillitial threads are remarkable for their graceful slenderness, regularity, and symmetry.

2. ARCYRIA OERSTEDTII _Rost._

1875. _Arcyria oerstedtii_ Rost., _Mon._, p. 278, Fig. 196.

Sporangia cylindric, arcuate, 1.5 mm. high when unexpanded, closely cl.u.s.tered, dull crimson, stipitate; peridium evanescent except here and there a persistent patch, the calyculus shallow, plicate, papillose within; stipe short, weak, concolorous; hypothallus distinct, membranous, concolorous; capillitium a loose, far-expanding, elastic net, the meshes uneven, often small, the threads characterized by much irregularity and many bulbose thickenings, especially at the nodes, strongly spinulose throughout; spore-ma.s.s crimson or reddish brown, dull; spores by transmitted light colorless, nearly smooth, sub-globose, 9-10 .

This well-marked species is certainly rare within our limits. We have specimens from New England and from Pennsylvania. The Iowa material referred to this species, _Bull. Lab. Nat. Hist. Ia._, II., p. 125, is _A. magna_ Rex. Rostafinski's figure is excellent in the present case, and gives the idea of what we regard the typical marking of the capillitium in _A. oerstedtii_. Externally the species resembles somewhat _A. nodulosa_, and the network of the capillitium is also suggestive of that form; the spiny capillitium is unique.

Rare. Adirondacks, New York--_Dr. Rex._

3. ARCYRIA NUTANS (_Bull._) _Grev._

PLATE II., Figs. 6, 6 _a_, 6 _b_.

1791. _Trichia nutans_ Bulliard, _Champ._, p. 122, t. 502, III.

1794. _Arcyria flava_ Pers., _Romer N. Mag. Bot._, I., p. 90.

1824. _Arcyria nutans_ Grev., _Fl. Edin._, p. 455.

Sporangia crowded, cylindric, about 2 mm. high when unexpanded, pale yellow or buff, short-stipitate or sessile by an acute base; peridium wholly evanescent, except at the base, where persists the shallow, colorless, often inwardly spinulose, plicatulate calyculus; stipe very short or wanting; hypothallus thin but usually in evidence; capillitium expanding to great length, forming an extremely flexile, plumose, pendulose open network of pale ochraceous tint, the threads 3-4 in thickness, adorned with spinules, sharp edged transverse plates sometimes rings, the surface especially marked by an indistinct reticulation; spore-ma.s.s buff or ochraceous, spores by transmitted light colorless, smooth or nearly so, 7-8 .

This elegant species is not rare in undisturbed woods, especially on fallen willows. The expanded capillitia are very soft and plume-like, waving and nodding, very lightly attached below to the centre of the peridial cup. The capillitium threads are rough, with irregular spines and sharp-edged transverse plates, occasionally extending to form rings.

Resembles the first species somewhat in habit, size, and the spinescent capillitium, but the resemblance is superficial only. The color is at once diagnostic, and the capillitium is after all entirely different.

Not uncommon; Canada to Mexico; Maine to California; probably cosmopolitan.

Bulliard's figure determines the synonymy. Persoon called the form _A.

flava_, because Bulliard had missed the genus.

4. ARCYRIA VERSICOLOR _Phillips._

1877. _Arcyria versicolor_ Phillips, _Grev._, V., p. 115.

1877. _Arcyria vitellina_ Phillips, _Grev._, V., p. 115.

Sporangia gregarious or more or less crowded, pyriform or clavate, dingy, olivaceous yellow, becoming reddish, stipitate; peridium membranous, largely persistent below, where it gives rise to the deep, goblet-shaped calyculus; stipe strand-like, weak, sometimes wanting, concolorous with the peridium; hypothallus prominent or venulose; capillitium only slowly expanded, bright golden yellow or orange, the threads rather broad, about 4 in diameter, regular, even, elegantly branching, adorned with abundant short spines or warts, very small and evenly distributed, the whole net anch.o.r.ed in the bottom of the vasiform calyculus; spore-ma.s.s yellow, by transmitted light pale or nearly colorless, smooth, about 10 .

This beautiful species is easily known by its comparatively large size, peculiar, obovate shape, its brilliant color, and unusually persistent membranous calyculus. It is peculiar to the western part of North America, South Dakota west to the Pacific Ocean.

South Dakota, Colorado, California, Washington.

In the thin-covered mountains of Colorado, or hidden by the still drier thickets and woods of Southern California, the fruit of this species is small, somewhat as the clavate hemitrichia, pure, deep yellow, golden or vitelline as Phillips says; but at loftier alt.i.tudes in the ever cool forests on the high mountain flanks, beginning away up where the glacier first starts to crack and slide between the 'cleavers', and forests of stunted white-stemmed pine or wooly-fruited fir throw down their twigs and foliage undisturbed through centuries,--on down to where the plowing ice forgets its thrust, and melts to gentle floods amid spruce and hemlock-groves,--all the way the beautiful versicolor spreads and fruits, in August and September in all the richness of color which its name implies, which Phillips saw, tints of red, and yellow, and olive, and green, not brilliant, but in all the softer shades the artists love, weaving, in far-spread strands of tufted cylinders and cones upturned, fair as flowers, dusky garlands, by sunlight long forgot! Did not the old-time botanists liken these things once and again, to flowers!

5. ARCYRIA INCARNATA _Persoon._

1786. _Clathrus adnatus_ Batsch, _Elench. Fung._, 141. (?) 1791. _Arcyria incarnata_ Pers., Gmel., _Syst. Nat._, II., 1467.

Sporangia closely crowded, cylindric, 1-1.5 mm. high, rosy or flesh-colored, stipitate or almost sessile; stipe generally short, sometimes barely a conical point beneath the calyculus; hypothallus none; peridium wholly evanescent, except the shallow, saucer-like, inwardly roughened calyculus; capillitium loose, broad, pale reddish, attached to the cup at the centre only by strands which enter the hollow stem, the threads adorned with transverse plates, cogs, ridges, etc., arranged in an open spiral; spore-ma.s.s rosy, spores by transmitted light colorless, nearly smooth, 7-8 .

This common species is well marked both by its color and by the delicate attachment of the capillitium to the calyculus. This is so frail that the slightest breath ofttimes suffices to effect a separation, and the empty calyculi are not infrequently the only evidence of the fructification. This peculiarity did not escape the attention of Persoon, and is well shown in his figure (_Obs. Myc._, I., p. 58, pl. V. Figs. 4 and 5) referred to by Gmelin, _l. c._ Batsch simply named and described Micheli's figure (Tab. XCIV., Fig. 2), and accordingly his claim to priority is no better than Micheli's figure, which may possibly concern the present species, but is in no sense determinative. It is impossible to say what Retzius meant by his _Clathrus ramosus_, cited by Fries as a synonym here.

Common, especially in the Mississippi valley and south; more rare in the west; Black Hills, South Dakota; Toronto to New Mexico.

6. ARCYRIA NODULOSA _Macbr._

PLATE III., Fig. 8.

Sporangia small, about 1 mm. high when unexpanded, crowded in cl.u.s.ters of varying size, dull red or brownish, stipitate; the peridium evanescent except the cup; stipe very short, concolorous, plicate as the cup, or both smooth and unmarked; capillitium centrally attached, slowly expanded, open-meshed, dense, the threads even, 5-6 wide, expanded in globose, spinulose, or papillate-reticulate nodules, especially at points of intersection, marked everywhere by close-set, transverse, sharp-edged ridges, which encircle the thread and show no trace of spiral arrangement; spore-ma.s.s brown or red brown; spores by transmitted light pale yellow or colorless, minutely but distinctly roughened, globose, 10-12 .

This variety is not distantly related to the preceding, as shown by the centrally attached capillitial ma.s.s, but differs in several definite particulars; the sporangia are much smaller of an entirely different color with longer stipes, larger, rougher spores; the capillitium is also peculiar, the threads unusually wide and densely corrugated transversely, expanding at frequent intervals into globose nodules which are sometimes double the width of the thread. In color suggests _A.

affinis_ Rost., but corresponds to no other particular.

7. ARCYRIA FERRUGINEA _Sauter._

PLATE XII., Figs. 6, 6 _a_, 6 _b_.

1841. _Arcyria ferruginea_ Saut., _Flora_, XXIV., p. 316.

1881. _Arcyria macrospora_ Peck, _Rep. N. Y. Mus._, x.x.xIV., p. 43.

1883. _Arcyria aurantiaca_ Raunier, _Myx. Dan._, p. (44).

Sporangia ovoid or short cylindric, crowded or gregarious, dull red or brownish, stipitate; stipe about equal to the sporangium, dark brown or black; hypothallus well developed, membranous, yellowish brown continuous; calyculus large, wide and shallow, smooth; capillitium centrally attached, when fresh, brick-red in color, fading on exposure, the threads of uneven size, those above 6-7 , below 3 , abundantly branching, marked by conspicuous reticulations formed by the intersection of numerous vertical plates or ridges; spore-ma.s.s reddish, spores by transmitted light pale ochraceous, distinctly warted, 10-12 .

This species is distinguishable at sight by the peculiar color and form of the sporangia. Mr. Durand in _Bot. Gaz._, XIX., pp 89, 90, gives a careful study of the form. The same author declares the dehiscence circ.u.mscissile. We cannot distinguish _A. aurantiaca_ Raun. from the present form.

Rare. Maine, New York; Monterey, California.

8. ARCYRIA DENUDATA (_Linn._) _Sheldon._

PLATE II., Figs. 5, 5 _a_.

1753. _Clathrus denudatus_ Linn., _Syst. Nat._, 1179.

1794. _Arcyria punicea_ Pers., _Rom. N. Mag. Bot._, I., p. 90.

1895. _Arcyria denudata_ (Linn.) Sheld., _Minn. Bot. Studies_, No. 9, p. 470.

Sporangia crowded or gregarious, ovoid or short cylindrical, tapering upward, red-brown, stipitate; peridium evanescent except the plicate calyculus; stipe about equal to the expanded capillitium, concolorous, plicate or striate, ascending from a small hypothallus; capillitium attached to the whole inner surface of the calyculus and connate with it; hence not deciduous, bright red or carmine when fresh, turning brown or paler with age, the threads even, about 3 adorned with a series of rather distant cogs or half rings, which form around the thread a lengthened spiral; spore-ma.s.s red or reddish brown, spores by transmitted light colorless, nearly smooth, 6-8 .

This species is easily distinguished from all other of similar tints by the attachment of the capillitium. In this respect it corresponds with the following species. In the adornment of the threads it is like _A.

incarnata_. It is by far the commonest species of the genus, and probably enjoys a world-wide distribution. To be found at all seasons on the lower side of fallen sticks, _Populus_, _Tilia_, etc.

Micheli, Pl. XCIV., shows that he had the present species. The description given by Linne is worthless, but helped out by Micheli, and several other authors of the eighteenth century, who take the trouble to describe the species, but still give the Linnean binomial as a synonym; we may give Linne here the credit. As a matter of fact, Batsch under _Embolus crocatus_ first presents an unmistakable description and figure.